Charged pion production and projectile breakup cIN 85A MEV C-12-Iinduced heavy-ion reactions

Charged pions have been measured at 70° in coincidence with projectile-like fragments in 12C + 12C, 12C + 116Sn and 12C + 124Sn reactions at 85A MeV. Neither the π+ emission nor the π-/π+ ratio exhibit differences for 124Sn and 116Sn targets outside those expected from the isospin difference. Inconsistencies in the target mass dependence of the pion yield disappear if a correction for reabsorption is included. After this correction, we observe a strong, ~ A1.1, mass dependence. The projectile breakup is significantly stronger for pion-producing collisions than for the average collision indicating a much stronger abundance of central collisions.